MT RS Symbol Encoder (shortened)

Generates a Reed-Solomon (RS) encoded integer symbol stream in a shortened format. In the shortened RS codes, the k and n values represent symbols. Each symbol has a length, m bits, specified using the bits per RS symbol parameter.

RS codes are specialized Bose-Chaudhari-Hocquenghem (BCH) codes in which the code elements are drawn from the Galois field, GF(2m). RS codes are extremely powerful at burst error correction. The operations involved in Reed-Solomon encoding and decoding are performed in the GF(2m). The RS encoder operates on code words that are symbols or groups of bits. The parameters code word length (n), symbols and data word length (k), symbols are specified in terms of symbols. Each symbol represents a group of Log2(n+1) bits.

Specify a shortened RS code by stating the shortened values of n and k, as well as the bits per symbol that correspond to the underlying Galois field arithmetic. For example, you can specify code word length (n), symbols as 32, data word length (k), symbols as 28, and bits per RS symbol as 8 to generate a shortened RS (32,28,2) code with error-correcting capacity of two RS symbols. For this code, the underlying Galois field arithmetic is performed in GF(28) = 256.

modulation session

The modulation session for configuring selected properties of the Modulation nodes. Use this parameter to configure the advanced properties in the MT RS Symbol Encoder nodes. If MT RS Symbol Encoder is called with an uninitialized modulation session, the node returns an error.

Default: 0

input symbols

The array of integer symbols to be encoded using the RS encoding scheme. Use MT Generate Bits followed by MT Pack Bits to generate the integer symbols required for this parameter.

Note

The RS encoder is a block encoder, which means that it operates on a block of k integers. To ensure that the output symbols stream corresponds to the entire input symbols array, set the length L of input symbols to be an integer multiple of k symbols. If the length L is not a multiple of k symbols, the last L modulo k symbols are buffered inside the encoder. These symbols are added to the incoming input symbols stream at the beginning of the next iteration if reset? is set to FALSE.

data word length (k), symbols

error in

Error conditions that occur before this node runs. The node responds to this input according to standard error behavior.

Default: no error

bits per rs symbol

The number of bits per Reed-Solomon (RS) symbol. This parameter sets the Galois field over which the encoding operation is performed as GF(2bits per rs symbol). Valid values are 3 to 16, inclusive. For example, to set a shortened RS (32,28) code in the Galois field GF(256), set code word length (n), symbol as 32 symbols, data word length (k), symbol as 28 symbols, and bits per rs symbol as 8.

Default: 3

reset?

A Boolean that determines whether the internal state of the encoder is cleared.

TRUE

Clears any buffered bits from previous iterations.Also initializes the Galois field structure corresponding to the Reed-Solomon n, k values.

FALSE

Continues encoding from the previous iteration. Any buffered bits from the previous iteration are added to the beginning of the input bit stream prior to encoding.